Setting gains with phone volume

[ItsHammer]

Horrible title, I know. Sorry. Anyway.. Setting gains on my Amp, should I treat my phone the same as my HU and only put volume at 2/3 or can I max out volum on my phone? I never play my music with phone volume maxed out anyway, but just curious if the gains would be correct if the volume isn't adjusted accordingly.

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[Lasherž]

Horrible title, I know. Sorry. Anyway.. Setting gains on my Amp, should I treat my phone the same as my HU and only put volume at 2/3 or can I max out volum on my phone? I never play my music with phone volume maxed out anyway, but just curious if the gains would be correct if the volume isn't adjusted accordingly.

I would keep the settings the same if I was going to use the amp for the head unit again and turn up the volume until you get a clip then never go above that. If you're not going to use it with a head unit any more then I'd say one tick under max should be fine. Phones shouldn't clip on any output, but that's going to be a lot of signal strength if you're going from 3.5mm to RCA. You may even have to turn it down to avoid clipping on zero gains depending entirely on your amp. Some amps accept high level outputs directly to RCAs.

 

[ItsHammer]

Oh OK. Thanks. One under max sounds reasonable

 

[THATpurpleKUSH 5,000+ posts]

The output voltage on phones from is at best 1v on a high end phone and about .6v .7v average on most other phones. You will need a line driver to boost the signal out of your phone because the signal is so weak. Without a line driver the signal will be so weak that maxing out the gain on the amp will get you barely any sound output.

I use a line driver to run test tones from my phone directly to my amp for spl purposes. My phone has been tested to output around .71v and the line driver bumps it up to about 4 or 5v. At minimum you should be giving the amp a 2.5v signal.

Still keep your phone volume below max volume, they will clip just like a regular headunit, just who knows at what point because no one has measured with an oscope and made a video of it.

 

[Lasherž]

The output voltage on phones from is at best 1v on a high end phone and about .6v .7v average on most other phones. You will need a line driver to boost the signal out of your phone because the signal is so weak. Without a line driver the signal will be so weak that maxing out the gain on the amp will get you barely any sound output.

I use a line driver to run test tones from my phone directly to my amp for spl purposes. My phone has been tested to output around .71v and the line driver bumps it up to about 4 or 5v. At minimum you should be giving the amp a 2.5v signal.

Still keep your phone volume below max volume, they will clip just like a regular headunit, just who knows at what point because no one has measured with an oscope and made a video of it.

Interesting, I'll have to test mine. I've gotten very strong signal with low gain and low volume on the phone. The voltage they put out is quite dependent on the resistance of the line, so maybe my amp has low input impedance.

My Note 9 also utilizes a 32bit DAC that probably contributes as well.

 

[THATpurpleKUSH 5,000+ posts]

Interesting, I'll have to test mine. I've gotten very strong signal with low gain and low volume on the phone. The voltage they put out is quite dependent on the resistance of the line, so maybe my amp has low input impedance.

Phonearena.com tests phones and audio output voltage is one of the test metrics. The highest tested output voltage was 1.941 with an HTC Desire 820. Iphones are usually around 1v, Galaxy 8 and 9s were around .65-.7v.

 

[Lasherž]

Phonearena.com tests phones and audio output voltage is one of the test metrics. The highest tested output voltage was 1.941 with an HTC Desire 820. Iphones are usually around 1v, Galaxy 8 and 9s were around .65-.7v.

Cool, I appreciate the resource. Do you think the 3.5mm output is low enough to cause feedback? I've been pretty lucky in avoiding it if that's the case.

 

[THATpurpleKUSH 5,000+ posts]

Cool, I appreciate the resource. Do you think the 3.5mm output is low enough to cause feedback? I've been pretty lucky in avoiding it if that's the case.

It should work like an RCA source, just don't use a weak signal to begin with or low quality cables. I use a 3.5mm to rca cable from my phone to the line driver then rcas to the amp. I only play test tones for spl burps because my application is not using a headunit or any other input source. I have a very unique application.